The present invention relates to methods for reducing the melt viscosity of vinylidene chloride containing polymers and compositions useful in these methods.
Ideally a solid solvent stays in a vinylidene chloride containing polymer at a use temperature as a microdispersed solid with little or no adverse affect on the use properties of the vinylidene chloride containing polymer.
Yet when the vinylidene chloride containing polymer and the solid solvent melt at a given processing temperature, the solid solvent becomes a solvent for the vinylidene chloride containing polymer effectively reducing the melt viscosity of the vinylidene chloride containing polymer. A reduced melt viscosity allows the use of a lower processing temperature which reduces the potential for thermal degradation of the vinylidene chloride containing polymer.
Plasticizers and lubricants are presently utilized to reduce the melt viscosity of vinylidene chloride containing polymers. Both have drawbacks over the use of a solid solvent. A plasticizer remains as a liquid dissolved in the vinylidene chloride containing polymer at use temperatures and thus adversely affects use properties. A lubricant remains virtually as a separate phase at processing temperatures and thus is not as effective as a solid solvent in reducing the melt viscosity of vinylidene chloride containing polymers.